I. Field of the Invention
The present invention is directed to pumps and pertains more particularly to a pumping device, preferably for pumping water but not limited thereto, which incorporates a new and novel design for a multiple-stage pump having a mere two (2) main components comprising a one-piece diffusion casing and a one-piece multiple turbine impeller.
II. Description of the Prior Art
In the prior art, turbine type pump housings have been formed by placing together a plurality of housing sections and joining the housing sections together at mating wall portions. Turbine centrifugal pumps have changed little since their development early in the twentieth century. As in most centrifugal pumps, water flow and pressure is produced as a result of a vaned impeller rotating on a shaft. The impeller forces water upward through a volute or "bowl" designed to be hydraulically compatible with the impeller. Each impeller is fastened to a central shaft and the resulting assembly is normally supported by an individual sleeve-type bushing and wear ring arrangement. Since the hydraulic design of the impeller within a bowl dictates the flow through the pump and the pressure delivered by the pump, performance conditions are virtually fixed at a given speed. However, pressure may be increased arithmetically by stacking or staging the impeller bowl combinations, provided the driving horsepower of the pump is also increased.
In effect, a multi-stage vertical turbine pump is assembled by stacking a pre-determined multitude of individual stages, which stages generally consist of a shaft impeller, bowl bearings, wear rings, bolting and casing. The materials from which the stages are constructed generally range from bronze to cast iron or plastic. The application and the concern for cost effectiveness usually dictates the materials which are employed in the construction of such pumps. With the increase in the number of parts within the prior art pumps to provide the number of stages required for a particular application, there comes a corresponding increase in the cost of the pump because of the multitude of parts involved and the difficulty by which the parts are manufactured and assembled.